"1. As the Instruction Dignitas Personae states, in cases where cells from aborted fetuses are employed to create cell lines for use in scientific research, “there exist differing degrees of responsibility” of cooperation in evil. For example, “in organizations where cell lines of illicit origin are being utilized, the responsibility of those who make the decision to use them is not the same as that of those who have no voice in such a decision”. 2. In this sense, when ethically irreproachable Covid-19 vaccines are not available (e.g. in countries where vaccines without ethical problems are not made available to physicians and patients, or where their distribution is more difficult due to special storage and transport conditions, or when various types of vaccines are distributed in the same country but health authorities do not allow citizens to choose the vaccine with which to be inoculated) it is morally acceptable to receive Covid-19 vaccines that have used cell lines from aborted fetuses in their research and production process. 3. The fundamental reason for considering the use of these vaccines morally licit is that the kind of cooperation in evil (passive material cooperation) in the procured abortion from which these cell lines originate is, on the part of those making use of the resulting vaccines, remote. The moral duty to avoid such passive material cooperation is not obligatory if there is a grave danger, such as the otherwise uncontainable spread of a serious pathological agent--in this case, the pandemic spread of the SARS-CoV-2 virus that causes Covid-19. It must therefore be considered that, in such a case, all vaccinations recognized as clinically safe and effective can be used in good conscience with the certain knowledge that the use of such vaccines does not constitute formal cooperation with the abortion from which the cells used in production of the vaccines derive. It should be emphasized, however, that the morally licit use of these types of vaccines, in the particular conditions that make it so, does not in itself constitute a legitimation, even indirect, of the practice of abortion, and necessarily assumes the opposition to this practice by those who make use of these vaccines. 4. In fact, the licit use of such vaccines does not and should not in any way imply that there is a moral endorsement of the use of cell lines proceeding from aborted fetuses. Both pharmaceutical companies and governmental health agencies are therefore encouraged to produce, approve, distribute and offer ethically acceptable vaccines that do not create problems of conscience for either health care providers or the people to be vaccinated. 5. At the same time, practical reason makes evident that vaccination is not, as a rule, a moral obligation and that, therefore, it must be voluntary. In any case, from the ethical point of view, the morality of vaccination depends not only on the duty to protect one's own health, but also on the duty to pursue the common good. In the absence of other means to stop or even prevent the epidemic, the common good may recommend vaccination, especially to protect the weakest and most exposed. Those who, however, for reasons of conscience, refuse vaccines produced with cell lines from aborted fetuses, must do their utmost to avoid, by other prophylactic means and appropriate behavior, becoming vehicles for the transmission of the infectious agent. In particular, they must avoid any risk to the health of those who cannot be vaccinated for medical or other reasons, and who are the most vulnerable."